The invention relates to a luminaire having a housing with a concave reflector with a plane of symmetry and a light emission window, and a holder for positioning an electric lamp in the plane of symmetry. The reflector has first opposing walls having flat strips extending along the plane of symmetry, second opposing walls transverse to the plane of symmetry, and a top wall opposite the light emission window.
Such a luminaire is disclosed in U.S. Pat. No. 5,564,820.
The known luminaire may be mounted in a ceiling. The flat strips of the first walls serve to spread the light generated by an accommodated lamp in directions transverse to the plane of symmetry. However, the strips do give rise to second reflections at the second walls. The second walls are flat, between straight bending lines along the light-emission window, so as to widen the light beam in the longitudinal direction of the lamp to be accommodated.
The known luminaire has the drawback that the reflector is voluminous, thus requiring the housing to be relatively large, particularly if the housing must accommodate means for feeding and starting the mounted lamp.
DE-A-1 904 982 discloses a luminaire in which reflectors are present in a housing situated at the side of a high-pressure discharge lamp arranged in a plane of symmetry. The reflectors are composed of flat strips extending along the light-emission window, and having a bending line in surfaces extending transversely to the light-emission window, the strips being bent towards each other along the bending line. The flat strips may flare out from the bending lines of the light-emission window. Opposite the light-emission window, the reflectors are covered with a flat reflector.
This luminaire too is very voluminous, while, in addition, the housing is closed with a dish-shaped transparent shield, parts of which extending perpendicularly to the light-emission window being used as an optical screen.